Chemistry:Calcium titanate

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Calcium titanate
CaTiO3 perovskite structure.png
Names
Other names
calcium titanium oxide
Identifiers
3D model (JSmol)
ChemSpider
RTECS number
  • XR2568666
UNII
Properties
CaTiO3
Molar mass 135.943 g/mol
Appearance white powder
Density 3.98 g/cm3
Melting point 1,975 °C (3,587 °F; 2,248 K)
Boiling point 3,000 °C (5,430 °F; 3,270 K)
insoluble
Hazards
Lethal dose or concentration (LD, LC):
>1200 mg/kg (oral, rat)
Thermochemistry
93.64 J/mol·K [1]
-1660.630 kJ/mol [1]
-1575.256 kJ/mol [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Calcium titanate is an inorganic compound with the chemical formula CaTiO3. As a mineral, it is called perovskite, named after Russian mineralogist, L. A. Perovski (1792-1856). It is a colourless, diamagnetic solid, although the mineral is often coloured owing to impurities.

Synthesis

CaTiO3 can be prepared by the combination of CaO and TiO2 at temperatures >1300 °C. Sol-gel processes has been used to make a more pure substance, as well as lowering the synthesis temperature. These compounds synthesized are more compressible due to the powders from the sol-gel process as well and bring it closer to its calculated density (~4.04 g/ml).[2]

Structure

Main page: Earth:Perovskite (structure)

Calcium titanate is obtained as orthorhombic crystals, more specifically perovskite structure.[3] In this motif, the Ti(IV) centers are octahedral and the Ca2+ centers occupy a cage of 12 oxygen centres. Many useful materials adopt related structures, e.g. barium titanate or variations of the structure, e.g. yttrium barium copper oxide.

Applications

Calcium titanate has relatively little value except as one of the ores of titanium, together with several others. It is reduced to give titanium metal or ferrotitanium alloys.[4]

See also

External links

References

  1. 1.0 1.1 1.2 Robie, R. A.; Hemmingway, B. S.; Fisher, J. R. (1978). "Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar pressure and at higher temperature". Geol. Surv. Bull.: 1452. doi:10.3133/b1452. Bibcode1978BUSGS.....1452R. https://digital.library.unt.edu/ark:/67531/metadc1114954/m2/1/high_res_d/report.pdf. 
  2. Dunn, Bruce; Zink, Jeffrey I. (September 2007). "Sol–Gel Chemistry and Materials". Accounts of Chemical Research 40 (9): 729. doi:10.1021/ar700178b. PMID 17874844. 
  3. Buttner, R. H.; Maslen, E. N. (1 October 1992). "Electron difference density and structural parameters in CaTiO3". Acta Crystallographica Section B 48 (5): 644–649. doi:10.1107/S0108768192004592. 
  4. Sibum, Heinz; Güther, Volker; Roidl, Oskar; Habashi, Fathi; Wolf, Hans Uwe (2000). "Titanium, Titanium Alloys, and Titanium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a27_095. ISBN 978-3-527-30673-2.